Front End for MAP Neutrino Factory/Collider rf considerations David Neuffer May 29, 2014
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Transcript Front End for MAP Neutrino Factory/Collider rf considerations David Neuffer May 29, 2014
Front End for MAP Neutrino Factory/Collider
rf considerations
David Neuffer
May 29, 2014
1
Outline
Previous baseline was 200 MHz (IDS nu Factory)
Rf, power req.
Front End for MAP NF/MC 325 MHz
Bunch train shorter than IDS …
With Chicane/Absorber
Current baseline
• Use short taper
Variations under study
2
325MHz System “Collider”
p
FE Target
π→μ
Drift
Solenoid
Drift
Buncher
Rotator
Cooler
14.75m
m
~42 m
~21.0 m
~24.0 m
~80 m
20T 2T
Buncher
Po=250MeV/c
PN=154 MeV/c; N=10
Vrf : 0 15 MV/m
• (2/3 occupied)
fRF : 490 365MHz
Rotator
Vrf : 20MV/m
• (2/3 occupied)
fRF : 364 326MHz
N=12.045
P0, PN245 MeV/c
Cooler
245 MeV/c
325 MHz
25 MV/m
2 1.5 cm LiH absorbers
/0.75m
3
325 Collider Update w/Chicane/Absorber
Chicane + Absorber
p
π μ
FE
Targ Solenoid
15m drift
et
+13m chicane
6 m +30.1 m drift
0.1 m
Be
Drift
Buncher
~22m
~21m
Rotator
Add 30 m drift after chicane
*6.5
m +15°,-15º
Add chicane + absorber
•
•
particle 1-283 MeV/c
particle 2-194 MeV/c
•
•
•
10 cm Be
particle 1-250 MeV/c
particle 2-154 MeV/c
•
Pref = 245 MeV/c
absorber at 41m
Bunch (N = 12) 015 MV/m: 496 365 MHz
Rotate (N=12.045 )– 20 MV/m: 365 326.5
MHz
Cool -325 MHz -25 MV/m
24 m
Cooler
~80 m
SREGION
! bentsol
6.5 1 1e-2
1 0. 1.0
BSOL
1 2.0 0.0 1 0.283 0.0 0.058181
0.0 0.0 0.0 0. 0. 0. 0. 0.
VAC
NONE
0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
ICOOL results
325 “muon collider” with chicane absorber
with added drifts between chicane and absorber
• ~30 m
~ 0.105 μ/p but smaller emittance beams
• scraped to better fit?
Change to shorter taper
15 m 6 m
(Hisham) slight improvement in throughput (~ 5%)
We are using Hisham’s more recent distributions
• Gains ~ 5-10%
• Total is now ~ 0.115 μ/p (in baseline ICOOL simulation units)
Better Rotator/Cooler match (Diktys)
+5%
Cooler will be replaced by better 6-D cooler (Alexahin)
5
Compare 325 w chicane vs old 200
High P cutoff is ~700 MeV/c (from ~500 MeV/c)
1.0 GeV/c
z=38m
0
z=137m
z=255m
6
Rf cavity
Concept
design
construction
operation
7
MAP rf properties (~ MICE rf)
Assume pillbox, Cu walls
Compare with MICE rf
Q = ~58000
a=0.574m, L=0.5, f=200MHz
Tt=0.83
P0 = 1.35 MW at 10MV/m
f=200MHz, L=0.5m,
E0=10MV/m
U0 = 62J, Tfill = 63.7μs
P0 = 3MW at 15MV/m
MICE rf
parameters
Value
Radius (mm)
610
Length (mm)
430
RT2 (M/m)
22
Power needed
(16MV/m)
4MW
Quality factor, Q0
54,000
Q0
2.405 Z0
1
2( f rf 0 ) 2 (1 La )
Rs Cu 0 f 0
2
E
U 0 0 L a 2 0.522 0
2
P0
Rs 0.5192 E02 a( L a)
Z02
sin
Tt
f rf L
c
f rf L
c
T fill Q0
ln(2.0)
f rf
8
rf
IDS RF requirements
Buncher
37 cavities (13 frequencies)
13 power supplies (~1—3MW)
RF Rotator
56 cavities (15 frequencies)
12 MV/m, 0.5m
~2.5MW (peak power) per cavity
Cooling System – 201.25 MHz
100 0.5m cavities (75m cooler), 15MV/m
~4MW /cavity
Front End
section
Length
#rf
cavities
frequencies
# of
freq.
rf gradient
rf peak power
requirements
Buncher
33m
37
319.6 to
233.6
13
4 to 7.5
~1 to 3.5 MW/freq.
Rotator
42m
56
230.2 to
202.3
15
12
~2.5MW/cavity
Cooler
75m
100
201.25MHz
1
15 MV/m
~4MW/cavity
Total drift)
~240m
193
29
~1000MV
~550MW
Magnet
Requirements:
9
rf
Rf Buncher/Rotator requirements
Buncher -21m
37 cavities (14 frequencies)
13 power supplies (~1—3MW)
RF Rotator -24m
64 cavities (16 frequencies)
20 MV/m, 0.25m
~2 MW (peak power) per cavity
Cooling System – 201.25 MHz
200 0.25m cavities (75m cooler), 25MV/m
~4MW /cavity
Front End
section
Length
#rf
cavities
frequencies
# of
freq.
rf gradient
rf peak power
requirements
Buncher
21m
37
484 to 365
14
0 to 16
0—1.34 MW/cavity
Rotator
24m
56
364to 326
16
20
~2.4 MW/cavity
Cooler
75m
200
325
1
25 MV/m
~3.7MW/cavity
Total
df+bxr+rttr
~134m
93
30
~500MV
140MW
10
First result on discretization
11
Dependence on rf gradient
With same cooling channel
25MV/m IDS 4-D cooling
Change Buncher/Rotator
peak rf voltage
0 –25 MV/m
0.14
0.12
0.1
0.08
0.06
0.04
Longer bunch train
captured with larger V’
0.02
0
0
5
10
15
20
25
20 MV/m
0 MV/m
10 MV/m
12
Dependence on Bfinal
13
Summary
We are studying 325 MHz based front end
produces more bunches in same length bunch train than 200 MHz
requires more bunches to be recombined ~12 21
• more difficult … ?
• HCC recombiner ?
Including chicane/absorber
• Improved matching
Would like to fit more μ in fewer bunches
14
Current Status
P5 process:
P5 Result:
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Supplemental slides
16
325 (w chicane/absorber)
~60 m long bunch train
1.0 GeV/c
~60 325 MHz buckets
0m
For collider choose “best 21
0.0 GeV/c
bunches “
(~19m)
65m
Includes ~2/3 of captured
μ’s
many are lost
21bunches are recombined
to 1 in collider scenario
It is more difficult to
recombine 21 than 12
Would like to extend
acceptance or generate
shorter train
93m
~ end of rotator
131m
~ After ~80m
215m
17
P5 result
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